1. Field of the Invention
The present invention relates to apparatus for cleaning and grinding medals, coins or the like.
2. Description of the Related Art
FIG. 7 of the accompanying drawings shows a conventional apparatus exclusively used for cleaning coins. The apparatus includes a cleaning conveyor C for receiving coins K from a hopper (not shown) and conveying them upward to the left, as seen in FIG. 7. The apparatus also includes a pair of cleaning rollers S in mutual contact, which are mounted downstream from the front end of the conveyor C. The apparatus further includes a pair of squeeze (wringer) rollers P in mutual contact, which are mounted downstream from the cleaning rollers S. Each of the lower rollers S and P is in compressive contact with a drive roller D. The apparatus further includes a cleaning brush B rotatably mounted above the conveyor C. The cleaning brush B can be rotated counterclockwise in FIG. 7. The apparatus further includes a means M for supplying cleaning fluid, which is positioned over the brush B. The cleaning fluid is a mixture of a large amount of cold or hot water and a capful (10 cc) of cleaner. Such an apparatus is disclosed in Japanese Patent Laid-Open Publications 10-277504 and 10-286534.
While the conveyor C is conveying coins K, with the cleaning brush B scraping and aligning them, they are cleaned with the cleaning fluid supplied from the supplying means M. The cleaned coins K pass between the cleaning rollers S and between the squeeze rollers P, which wipe the liquid off the coins before the coins are discharged out of the apparatus. When the coins K pass between the cleaning rollers S and between the squeeze rollers P, metal powder or other foreign substances on the coins may be transferred to and stick to the cylindrical surfaces of the rollers. This soon decreases the ability of the roller surfaces to absorb water. As a result, the apparatus discharges wet coins K, which are apt to rust. It is therefore necessary to frequently remove and clean the rollers. Some cleaning apparatuses of this type include cleaning rollers and squeeze rollers easy to remove by hand. Other cleaning apparatuses of this type include cleaning rollers and squeeze rollers of a cassette type. It is still, however, troublesome work to remove and clean the rollers of these apparatuses. In addition, it is necessary to clean the flush tank of such an apparatus once a day. Furthermore, because the drive rollers D are made of stainless material, they are hard and may apply high pressure on the cleaning rollers S and squeeze rollers P, so that the rollers S and P may be damaged.
An object of the present invention is to provide a coin cleaning and grinding apparatus which operates without the problems that would arise if the cleaned coins were wiped by rollers. Another object is to provide an apparatus which includes rollers for grinding coins, wherein the rollers are cleaned constantly by being sprinkled directly with an abrasive liquid that does not rust coins, coins pass and are ground between the rollers, and wherein the rollers neither need frequently removing and cleaning, nor are damaged.
A coin cleaning and grinding apparatus according to the present invention includes a conveyor for conveying coins. The apparatus also includes first and second drive rollers mounted rotatably and horizontally in parallel with each other. The apparatus further includes a pair of primary grinding rollers and a pair of secondary grinding rollers. The grinding rollers are mounted rotatably and in parallel with the drive rollers. The primary grinding rollers are positioned downstream from the conveyor. One of the primary grinding rollers is positioned lower than the other. The lower primary grinding roller is in compressive contact with the higher primary grinding roller and the first drive roller. The secondary grinding rollers are positioned downstream from the primary grinding rollers. One of the secondary grinding rollers is positioned lower than the other. The lower secondary grinding roller is in compressive contact with the higher secondary grinding roller and the second drive roller. The apparatus further includes a sprinkling plate positioned at an angle above the grinding rollers. The sprinkling plate has first and second rows of sprinkling holes through which abrasive liquid can be sprinkled onto the grinding rollers. The first row of sprinkling holes are formed above and in parallel with the primary grinding rollers slightly upstream from their axes. The second row of sprinkling holes are formed above and in parallel with the secondary grinding rollers slightly upstream from their axes.
The drive rollers may be made of urethane sponge having a urethane hardness between 70 and 90 degrees. The grinding rollers may each include a shaft made of vinyl chloride and a grinding sleeve made of urethane sponge. The sleeve is press-fitted around and adheres to the shaft.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages, specific objects attained by its use, reference should be had to the drawing and descriptive matter in which there are illustrated and described preferred embodiments of the invention.